Restoring a Kerrihard power hammer - advice?

[JNewman]

My suggestions for doing it are either to machine the guides and dowel them and the back strips to a piece of Blanchard ground plate.  The dowels would contain any side to side motion  Then the mounting bolts would hold the whole thing together,  No welding to warp the plate and no expensive dovetail cutter ($300 ) needed. 

 

Or

 

Simple pattern with follow board  1 1/2 -2 hours.  Then cast in ductile iron and 1/8" machining plus machining in the dovetail. 

[ciladog]

I was thinking the same thing but I reckoned welding it together would warp it too much...... :huh:

 

You always make a weldment larger than the finished product.  If you did the welding correctly and did some stress releaving you will have enough material to machine the part.  You do get distortion when welding but if you plan for it you can machine it out in the finel product.

[peacock]

If I were fixing this hammer my first step would be to remachine the ram to make sure it is true and straight.  Then I would weld up the new guide with extra stock for machining.  I would bolt this to the frame and heat it to a dull red with a rosebud then tighten the bolts carefully then let it cool completely.  Then I would remove it and machine to fit the ram.

 

The ram and frame are not  likely to be true. if you machine a new guide without addressing these problems first you could break your frame when you bolt a new straight guide to it or warp the new guide. causeing the ram to bind.   By heating the weldment and bolting it to the frame it will seat it's self to the frame. 

[Tommy Traylor]

Cast iron will hold lubrication better and therefore last longer.

[ciladog]

I for one have really been overthinking this part.  The eaisest and cheapest way to make it is from 5 pieces of cold rolled stock.  One 3/8" plate, 2 3/8 X 1-1/4 bars, and 2 7/8 X 1-1/2 bars.  There is no welding, no distortion, and can be made with a drill press and something to cut or grind the 60 degree dovetail.

 

Four 3/8 " capscrews hold it together until it gets bolted to the hammer and then then the six 1/2" bolts lock it all in place.

 

Attached is a drawing I did this morning for the fun of it but some of the dimensions are not included as Ogmios's drawings did not include them.  And I was not sure if the dimensions were from hole centers or to the edge of the holes.

 

 

[JNewman]

I for one have really been overthinking this part. The eaisest and cheapest way to make it is from 5 pieces of cold rolled stock. One 3/8" plate, 2 3/8 X 1-1/4 bars, and 2 7/8 X 1-1/2 bars. There is no welding, no distortion, and can be made with a drill press and something to cut or grind the 60 degree dovetail.

Four 3/8 " capscrews hold it together until it gets bolted to the hammer and then then the six 1/2" bolts lock it all in place.

Attached is a drawing I did this morning for the fun of it but some of the dimensions are not included as Ogmios's drawings did not include them. And I was not sure if the dimensions were from hole centers or to the edge of the holes.

That is essentially what I am suggesting except using hardened steel dowel pins rather than the capscrews. I like dowels for something like this as bolts will allow side to side movement.

[ciladog]

That is essentially what I am suggesting except using hardened steel dowel pins rather than the capscrews. I like dowels for something like this as bolts will allow side to side movement.

I hear you but sometimes a little movement on something is a good thing for final alinement.

[ogmios]

Wow, thanks folks! Ciladog's diagram is awesome, thanks for taking the time! FYI, I put the whole thing back together last night, ram, broken guide, and all, and cycled by hand after adding oil. Runs very nicely, if with a bit too much play owing to the broken guide. Still, makes me smile just to stand there turning the thing, after a decade :) Patrick

[ogmios]

Greetings!

 

I'm a bit late in posting this update, but just to let you all know, I've now got a replacement ram guide!

 

Two pics attached of the piece.  It fits like a glove, and the ram moves perfectly up and down.  One step closer to the dream :)  Now, waiting for juuuust the right motor to go on sale...

 

Patrick

[macbruce]

Sweet, looks like a first rate job..... B)

[g19605]

I have a Kerrihard and at one time I had more questions than you had. I got mine nearly ten years ago and just recently got around to working on it, It was kind of a basket case and was missing some major parts. I had to make a new eccentric shaft and a new upper shaft all with the associated washers and nuts. These are 1 7/16" -11 1/2 thd and 1 5/16" - 11 1/2 thd, respectively. Strange thread pitch  for use on machinery --the small size is 1" pipe thread. I'm going to put a light Belleville washer between the pulley and clutch plate just  to ensure  that separation is maintained during idling.
 
The "ram" on mine weighs 33 pounds with the anvil installed . It has some embossed letters but only the upper (CAST)  and lower (STEEL) are easy to read. In between there is an unknown character followed by what appears to be a 5. Do you (or anyone) know what I have?
 
I'd like to learn the correct set-up procedure, ie where the anvil position should be when the springs are horizontal and maybe lots of other helpful hints. Maybe other guys can chime in.
 
This hammer was used for many years by a Blacksmith in Reading PA .
 
George